On Tue, 12 Nov 2019 at 05:59, Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote: > > On 09/11/19 08:05, Wanpeng Li wrote: > > From: Wanpeng Li <wanpengli@xxxxxxxxxxx> > > > > After disabling mwait/halt/pause vmexits, RESCHEDULE_VECTOR and > > CALL_FUNCTION_SINGLE_VECTOR etc IPI is one of the main remaining > > cause of vmexits observed in product environment which can't be > > optimized by PV IPIs. This patch is the follow-up on commit > > 0e6d242eccdb (KVM: LAPIC: Micro optimize IPI latency), to optimize > > redundancy logic before fixed mode ipi is delivered in the fast > > path. > > > > - broadcast handling needs to go slow path, so the delivery mode repair > > can be delayed to before slow path. > > I agree with this part, but is the cost of the irq->shorthand check > really measurable? I can drop the second part for v2. Wanpeng